Creating a pushbutton and callback function

Question

K VdB 2016-10-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/308842-creating-a-pushbutton-and-callback-function

评论： Walter Roberson 2021-11-26

采纳的回答： Mischa Kim

在 MATLAB Online 中打开

I could not find the right answer after a long search.

I want to create several pushbuttons in the script:

PushButton = uicontrol(gcf,'Style', 'push', 'String', 'Next', ... 'Position', [300 10 30 30], ...
'CallBack', 'PushB');

Then when I push the pushbutton I want the program to run a related function

function PushB_Callback('variables')
display('I pushed the pushbutton')
end

How do I do this?

thanks

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Answer 1

Mischa Kim 2016-10-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/308842-creating-a-pushbutton-and-callback-function#answer_240397

编辑：Mischa Kim 2016-10-24

在 MATLAB Online 中打开

Try

function myButtonTest()
PushButton = uicontrol(gcf,'Style', 'push', 'String', 'Next','Position', [300 10 30 30],'CallBack', @PushB);
function PushB(source,event)
display('I pushed the pushbutton')
end
end

For more information, check out the example in the documentation.

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Mischa Kim 2016-10-24

@Simon: Absolutely. I just copy-pasted the code without replacing the quotation marks. Thanks.

K VdB 2016-10-24

It works! Fantastic!

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Answer 2

Jan 2016-10-24

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/308842-creating-a-pushbutton-and-callback-function#answer_240411

编辑：Jan 2016-10-26

在 MATLAB Online 中打开

Use a function handle:

function main()
PushButton = uicontrol(gcf,'Style', 'push', 'String', 'Next', ...
            'Position', [300 10 30 30], ...
            'CallBack', @PushB_Callback);  % [EDITED, Typo: "_Callback" added]
end
function PushB_Callback(ObjectH, EventData)
display('I pushed the pushbutton')
end

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Brian Njenga 2021-11-26

What is ObjectH in the function handle

Walter Roberson 2021-11-26

@Brian Njenga

In MATLAB, callback functions are automatically passed at least two parameters.

The first parameter is the handle of the object for which the callback is taking place. This allows you to use the same callback function for different objects, with the function using the passed-in handle to know which object it was invoked for. So in the case of this sample code, the first parameter, here called ObjectH, will be passed as the handle of the uicontrol -- it will have the same value as PushButton has.

The second parameter is event information that describes in more detail what was requested. For most kinds of callbacks, there is no additional information and [] is passed. For some kinds of callbacks such as WindowsButtonPressFcn the parameter is a struct that has information about which button (or key) was pressed, or what the current bounds are (for constraint callbacks), and so on.

For uicontrol associated with "traditional" figures, when using Callback, then the event data will be a object of type ActionData, that has a property Source (which will be a handle to the control that was activated), and property EventName, which will be the character vector with content 'Action'

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